Tormania

Imagine my surprise when I was coming home from work yesterday and about 2 miles from home my DIC alerted me that my coolant temp was abnormally high, 264 degrees to be exact. It continued to climb until it exceeded 280 and the DIC simply said "Coolant Temp Hi". At this point the computer put the car in Reduced Engine Power mode. Luckily I was close enough to home that I simply limped the car home for a couple minutes, my oil temp never exceeding 234 degrees, normal summer temp so that was good.

I pop the hood, notice no leaks, no drips, just the slight smell of hot coolant. So I let the car cool down overnight and this morning I checked to see if I was low on coolant and decided to add about 1-2 cups of coolant. I wait a bit after adding it and then hear the sound of fluid pouring on the garage floor.

After jacking the car up my fears were confirmed, the radiator stop-**** was gone!! No wonder the car overheated the day before. I had had the coolant drained some and refilled about 4 weeks earlier but all had been well until yesterday afternoon. I know there are some bad bumps on the way home, perhaps on of those bumps was just enough to dislodge the stop-****??? So the car is disabled at home while I get a replacement part (dealer has it in stock luckily) and then get some coolant and distilled water to fill it back up.

I was surprised that the radiator uses a stop-**** rather then a threaded plug like the oil pan has. Just can't figure out how the darn thing got loose enough to come off. Glad I was close to the house though.

IDM

wow, can't you just replace that part instead of getting a new radiator? I might not know what you are referring to.

Also, I have read on this forum that the C5 was made to be able to run without coolant at all in the block so you most likely didn't damage anything by running it that high for a few minutes.

Tormania

Yes, I only have to get a new plug($6) compared to a new radiator and then the cost of having to replace that.

rcarl

Really, it can be run without coolant? Can someone point me to the factoid on that? Sounds like a lump of melted alloy is on order driving without coolant! And the OP stated the dealer had the replacement part, never said new radiator.

DIXZ

The factoid can be found in the owners manual, (page 5-26 in the 2003 manual):

Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
messages COOLANT OVER TEMP and REDUCED
ENGINE POWER are displayed, along with the Check
Engine light, an overheat protection mode which
alternates firing groups of cylinders helps prevent engine
damage. In this mode, you will notice a loss in power
and engine performance. This operating mode
allows your vehicle to be driven to a safe place in an
emergency; you may drive up to 50 miles (80 km).
Notice: After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attemptinga ny
repair. The engine oil will be severely degraded.
Repair the cause of coolant loss, change the oil
and reset the oil life systemS. ee “Engine Oil” in
the Index.

rcarl

WOW! and I've actually read the manual and don't recall seeing that. I still don't know if I'd rely on the computer not failing and protecting from a meltdown. I think I'd pull over and get flat-bedded home.

dougbfresh

That's bad when your DIC complains about your petCOCK.

liljohnny555